1. Field of the Invention
The present invention relates to a sheet feeding device and an image forming apparatus including the sheet feeding device.
2. Description of the Related Art
Conventionally, there is known a sheet feeding device with a tray on which a sheet to be fed, such as an original or a sheet of paper on which an image is to be formed, is mounted so that the sheet can be fed from the end thereof; the tray is configured to be foldable according to the size of a sheet to be fed in a sheet feeding direction.
For example, Japanese Laid-open Patent Publication No. 2000-128367 and Japanese Laid-open Patent Publication No. H6-298382 have disclosed a foldable paper feeding tray that includes a tray main body and a cover member; the cover member is rotatably connected to the tray main body and can move rotationally between a closed position where the cover member covers a first mount surface of the tray main body and an open position where the first mount surface is exposed. At an edge of the tray main body on the side opposite to a sheet feeding side, hinge parts (connecting parts) are installed on both ends of the tray main body in a width direction perpendicular to a sheet feeding direction, respectively. The hinge parts have a rotating shaft installed on the side of the tray main body and a movable arm part capable of moving rotationally about the rotating shaft; the cover member is connected to the tip of the movable arm part. This cover member is supported by the movable arm parts of the hinge parts so that an edge of the cover member on the side of the rotation center is opposed to the edge of the tray main body through a predetermined gap (a sheet insertion slot) when the cover member has rotationally moved to the closed position where the cover member covers the first mount surface of the tray main body. A sheet can be inserted into this sheet insertion slot and mounted on the first mount surface of the tray main body. On the other hand, when the cover member has rotationally moved to the open position where the first mount surface of the tray main body is exposed, a large-size sheet can be mounted on over the first mount surface of the tray main body and an upper surface (a second mount surface) of the cover member.
In the paper feeding tray disclosed in any of Japanese Laid-open Patent Publication No. 2000-128367 and Japanese Laid-open Patent Publication No. H6-298382, it is necessary to form the sheet insertion slot composed of the predetermined gap between the tray main body and the cover member which are opposed to each other on the side opposite to the sheet feeding side of the tray main body. Therefore, the movable arm parts of the hinge parts supporting the cover member increase in length, thereby the rigidity of the hinge parts is low. If the rigidity of the hinge parts is low, when the cover member is rotationally moved to the open position where the first mount surface of the tray main body is exposed to hold large-size sheets on the first mount surface of the tray main body and the second mount surface of the cover member, the hinge parts may be damaged according to the load of the sheets.
In the paper feeding tray disclosed in Japanese Laid-open Patent Publication No. H6-298382, if it is used with the cover member in a closed state in which the cover member has rotationally moved to the closed position, when a sheet is inserted into the sheet insertion slot and is mounted on the first mount surface of the tray main body, the leading end of the sheet is hard to be seen. Therefore, the leading end of the sheet may possibly enter between an upper end of a side fence and the underside of the cover member, resulting in a sheet setting failure.